Removed fixed dependencies

packages/crypto/CHANGELOG.md

+## 2.0.2
+
+* Prepare `HashSink` implementation for limiting integers to 64 bits in Dart
+  language.
+
+## 2.0.1
+
+* Support `convert` 2.0.0.
+
+## 2.0.0
+
+**Note**: There are no APIs in 2.0.0 that weren't also in 0.9.2. Packages that
+would use 2.0.0 as a lower bound should use 0.9.2 instead—for example, `crypto:
+">=0.9.2 <3.0.0"`.
+
+* `Hash` and `Hmac` no longer extend `ChunkedConverter`.
+
+## 1.1.1
+
+* Properly close sinks passed to `Hash.startChunkedConversion()` when
+  `ByteConversionSink.close()` is called.
+
+## 1.1.0
+
+* `Hmac` and `Hash` now extend the new `ChunkedConverter` class from
+  `dart:convert`.
+
+* Fix all strong mode warnings.
+
+## 1.0.0
+
+* All APIs that were deprecated in 0.9.2 have been removed. No new APIs have
+  been added. Packages that would use 1.0.0 as a lower bound should use 0.9.2
+  instead—for example, `crypto: ">=0.9.2 <2.0.0"`.
+
+## 0.9.2+1
+
+* Avoid core library methods that don't work on dart2js.
+
+## 0.9.2
+
+* `Hash`, `MD5`, `SHA1`, and `SHA256` now implement `Converter`. They convert
+  between `List<int>`s and the new `Digest` class, which represents a hash
+  digest. The `Converter` APIs—`Hash.convert()` and
+  `Hash.startChunkedConversion`—should be used in preference to the old APIs,
+  which are now deprecated.
+
+* `SHA1`, `SHA256`, and `HMAC` have been renamed to `Sha1`, `Sha256`, and
+  `Hmac`, respectively. The old names still work, but are deprecated.
+
+* Top-level `sha1`, `sha256`, and `md5` fields have been added to make it easier
+  to use those hash algorithms without having to instantiate new instances.
+
+* Hashing now works correctly for input sizes up to 2^64 bytes.
+
+### Deprecations
+
+* `Hash.add`, `Hash.close`, and `Hash.newInstance` are deprecated.
+  `Hash.convert` should be used for hashing single values, and
+  `Hash.startChunkedConversion` should be used for hashing streamed values.
+  
+* `SHA1` and `SHA256` are deprecated. Use the top-level `sha1` and `sha256`
+  fields instead.
+
+* While the `MD5` class is not deprecated, the `new MD5()` constructor is. Use
+  the top-level `md5` field instead.
+
+* `HMAC` is deprecated. Use `Hmac` instead.
+
+* `Base64Codec`, `Base64Encoder`, `Base64Decoder`, `Base64EncoderSink`,
+  `Base64DecoderSink`, and `BASE64` are deprecated. Use the Base64 APIs in
+  `dart:convert` instead.
+
+* `CryptoUtils` is deprecated. Use the Base64 APIs in `dart:convert` and the hex
+  APIs in the `convert` package instead.
+
+## 0.9.1
+
+* Base64 convert returns an Uint8List
+* Base64 codec and encoder can now take an encodePaddingCharacter
+* Implement a Base64 codec similar to codecs in 'dart:convert'
+
+## 0.9.0
+
+* ChangeLog starts here.